title: A simple assay to amplify the electrochemical signal by the aptamer based biosensor modified with CdS hollow nanospheres.
abstract: A simple method to amplify the electrochemical signal by an aptamer with 22 bases modified with CdS hollow nanospheres (CdSHNs) was described. Using the thrombin as a model, the interaction between the aptamer and CdSHNs was characterized by cyclic voltammetry, electrochemical impedance spectroscopy and circular dichroism spectroscopy. CdSHNs promoted the electron transfer between the gold electrode and K(3)[Fe(CN)(6)] and facilitated the conformation conversion of the aptamer from hairpin to G-quadruplex after the aptamer interacted with thrombin. Under optimal conditions, the modified electrode could be used for the determination of thrombin from 0 to 33 μg mL(-1) and the sensitivity was 1.34 μA mL μg(-1)cm(-2), while the linear range of the modified electrode without the immobilization of CdSHNs was from 2.75 to 27.5 μg mL(-1) and the sensitivity was 0.062 μA mL μg(-1)cm(-2). This constructed biosensor also had a good stability, specificity, reproducibility and accuracy which could provide a promising platform for fabrication of aptamer based biosensors.
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, Laboratory of Electrochemistry, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097, PR China.
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Li
authors.forename: Jianchun
authors.initials: J
authors.lastname: Bao
authors.forename: Min
authors.initials: M
authors.lastname: Han
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Dai
authors.forename: Huaisheng
authors.initials: H
authors.lastname: Wang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry*; D002942:Circular Dichroism; D055664:Electrochemical Techniques / Q000379:methods*; D006801:Humans; D054118:Nanospheres / Q000737:chemistry*; D015203:Reproducibility of Results; D013440:Sulfides / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide; D013917:Thrombin